Hi,
except for the following two patches:
fd7d55172d1e ("perf/cgroups: Don't rotate events for cgroups unnecessarily")
7fa343b7fdc4 ("perf/core: Fix corner case in perf_rotate_context()")
And this patch is also needed:
90c91dfb86d0 ("perf/core: Fix endless multiplex timer")
Would you please merge them into the 4.19 stable branch? Thanks
-- Best wishes， Wen
在 2021/6/7 下午3:59, Wen Yang 写道:
From: Ian Rogers irogers@google.com
[ Upstream commit fd7d55172d1e2e501e6da0a5c1de25f06612dc2e ]
Currently perf_rotate_context assumes that if the context's nr_events != nr_active a rotation is necessary for perf event multiplexing. With cgroups, nr_events is the total count of events for all cgroups and nr_active will not include events in a cgroup other than the current task's. This makes rotation appear necessary for cgroups when it is not.
Add a perf_event_context flag that is set when rotation is necessary. Clear the flag during sched_out and set it when a flexible sched_in fails due to resources.
Signed-off-by: Ian Rogers irogers@google.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Arnaldo Carvalho de Melo acme@kernel.org Cc: Arnaldo Carvalho de Melo acme@redhat.com Cc: Borislav Petkov bp@alien8.de Cc: Jiri Olsa jolsa@redhat.com Cc: Kan Liang kan.liang@linux.intel.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Stephane Eranian eranian@google.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Vince Weaver vincent.weaver@maine.edu Link: https://lkml.kernel.org/r/20190601082722.44543-1-irogers@google.com Signed-off-by: Ingo Molnar mingo@kernel.org Cc: stable@vger.kernel.org # 4.19+ Signed-off-by: Wen Yang wenyang@linux.alibaba.com
include/linux/perf_event.h | 5 +++++ kernel/events/core.c | 42 ++++++++++++++++++++++-------------------- 2 files changed, 27 insertions(+), 20 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index d8b4d31..efe30b9 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -747,6 +747,11 @@ struct perf_event_context { int nr_stat; int nr_freq; int rotate_disable;
- /*
* Set when nr_events != nr_active, except tolerant to events not* necessary to be active due to scheduling constraints, such as cgroups.*/- int rotate_necessary; atomic_t refcount; struct task_struct *task;
diff --git a/kernel/events/core.c b/kernel/events/core.c index b8b74a4..56e3789 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2952,6 +2952,12 @@ static void ctx_sched_out(struct perf_event_context *ctx, if (!ctx->nr_active || !(is_active & EVENT_ALL)) return;
- /*
* If we had been multiplexing, no rotations are necessary, now no events* are active.*/- ctx->rotate_necessary = 0;
- perf_pmu_disable(ctx->pmu); if (is_active & EVENT_PINNED) { list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
@@ -3319,10 +3325,13 @@ static int flexible_sched_in(struct perf_event *event, void *data) return 0; if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
if (!group_sched_in(event, sid->cpuctx, sid->ctx))list_add_tail(&event->active_list, &sid->ctx->flexible_active);else
int ret = group_sched_in(event, sid->cpuctx, sid->ctx);if (ret) { sid->can_add_hw = 0;sid->ctx->rotate_necessary = 1;return 0;}list_add_tail(&event->active_list, &sid->ctx->flexible_active);return 0; @@ -3690,24 +3699,17 @@ static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event) static bool perf_rotate_context(struct perf_cpu_context *cpuctx) { struct perf_event *cpu_event = NULL, *task_event = NULL;
- bool cpu_rotate = false, task_rotate = false;
- struct perf_event_context *ctx = NULL;
- struct perf_event_context *task_ctx = NULL;
- int cpu_rotate, task_rotate;
/* * Since we run this from IRQ context, nobody can install new * events, thus the event count values are stable. */
- if (cpuctx->ctx.nr_events) {
if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)cpu_rotate = true;- }
- ctx = cpuctx->task_ctx;
- if (ctx && ctx->nr_events) {
if (ctx->nr_events != ctx->nr_active)task_rotate = true;- }
- cpu_rotate = cpuctx->ctx.rotate_necessary;
- task_ctx = cpuctx->task_ctx;
- task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
if (!(cpu_rotate || task_rotate)) return false; @@ -3716,7 +3718,7 @@ static bool perf_rotate_context(struct perf_cpu_context *cpuctx) perf_pmu_disable(cpuctx->ctx.pmu); if (task_rotate)
task_event = ctx_first_active(ctx);
task_event = ctx_first_active(task_ctx);@@ -3724,17 +3726,17 @@ static bool perf_rotate_context(struct perf_cpu_context *cpuctx) * As per the order given at ctx_resched() first 'pop' task flexible * and then, if needed CPU flexible. */
- if (task_event || (ctx && cpu_event))
ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
- if (task_event || (task_ctx && cpu_event))
ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);if (task_event)
rotate_ctx(ctx, task_event);
rotate_ctx(task_ctx, task_event);
- perf_event_sched_in(cpuctx, ctx, current);
- perf_event_sched_in(cpuctx, task_ctx, current);
perf_pmu_enable(cpuctx->ctx.pmu); perf_ctx_unlock(cpuctx, cpuctx->task_ctx);